From de35d4e2d39298cef4736d464324f80d080fa34a Mon Sep 17 00:00:00 2001
From: KKlochko <KKlochko@protonmail.com>
Date: Thu, 12 Oct 2023 22:04:39 +0300
Subject: [PATCH] Add the function to make a frequency string from a map.

---
 .../symbols/{frequences.clj => frequencies.clj}    | 14 ++++++++++++--
 .../symbols/frequencies_test.clj                   | 11 +++++++++++
 2 files changed, 23 insertions(+), 2 deletions(-)
 rename src/cipher_analytical_machine/symbols/{frequences.clj => frequencies.clj} (69%)
 create mode 100644 test/cipher_analytical_machine/symbols/frequencies_test.clj

diff --git a/src/cipher_analytical_machine/symbols/frequences.clj b/src/cipher_analytical_machine/symbols/frequencies.clj
similarity index 69%
rename from src/cipher_analytical_machine/symbols/frequences.clj
rename to src/cipher_analytical_machine/symbols/frequencies.clj
index c9e0ac4..dad6368 100644
--- a/src/cipher_analytical_machine/symbols/frequences.clj
+++ b/src/cipher_analytical_machine/symbols/frequencies.clj
@@ -1,7 +1,17 @@
 (ns cipher-analytical-machine.symbols.frequencies
   (:gen-class))
 
-(def english-letter-frequences {
+(defn map-to-string
+  "Convert the map of frequencies to the frequency string. Letters are sorted by frequency in descending order."
+  [frequency-map]
+  (->> frequency-map
+       (reduce (fn [acc el] (conj acc el)) [])
+       (sort-by last)
+       (map first)
+       (reverse)
+       (apply str)))
+
+(def english-letter-frequencies {
    \a 0.0804
    \b 0.0154
    \c 0.0306
@@ -30,7 +40,7 @@
    \z 0.0009
 })
 
-(def ukrainian-letter-frequences {
+(def ukrainian-letter-frequencies {
    \а 0.064
    \б 0.013
    \в 0.046
diff --git a/test/cipher_analytical_machine/symbols/frequencies_test.clj b/test/cipher_analytical_machine/symbols/frequencies_test.clj
new file mode 100644
index 0000000..1db5bd0
--- /dev/null
+++ b/test/cipher_analytical_machine/symbols/frequencies_test.clj
@@ -0,0 +1,11 @@
+(ns cipher-analytical-machine.symbols.frequencies-test
+  (:require
+   [clojure.test :refer :all]
+   [cipher-analytical-machine.symbols.frequencies :refer :all]))
+
+(deftest calculate-char-index-test
+  (let [symbol-map english-letter-frequencies]
+    (testing "The map must be converted to 'etaoinsrhldcumfpgwybvkxjqz'"
+      (is (= "etaoinsrhldcumfpgwybvkxjqz"
+             (map-to-string symbol-map))))))
+